<!DOCTYPE html>
<html lang="en">

<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
    <style>
        p {
            color: blue;
        }

        #intro p {
            color: green;
        }

        .special {
            color: red;
        }
    </style>
</head>

<body>
    <div id="intro">
        <p class="special">This is a paragraph.</p>
    </div>
</body>

</html>